Many customers of electricity, particularly light commercial establishments and residences having central air conditioning, use three phase circuitry wherein one power leg provides 200 volts. It is estimated, however, that approximately 10 percent of all establishments provided with three phase wiring and therefore three phase electrical meters do not actually have any three phase equipment. This occurs for a variety of reasons. For example, a customer may replace the three phase equipment on the premises and therefore no longer require three phase power. In some cases, a change of tenants obviates the need for three phase power supply.
When the need for three phase power no longer exists, two forms of inefficiency arise. With respect to the consumer, he is still paying for electricity on the basis of at least two, factors. The first factor is the consumer's actual use of energy, expressed in kilowatt hours. The second factor is a charge to the consumer with respect to his average "connected load" which reflects the utility company's fixed charges of interest and depreciation on its investment of the equipment necessary to meet the maximum power requirements of that particular customer. Simply stated, the customer is therefore paying for a more expensive three phase meter and a shared cost for a line transformer adjacent to his site of consumption which conditions the voltage and current for expected three phase use. Typically, a consumer will have to bear a monthly minimum meter charge of three dollars ($3.00) for a three phase meter as opposed to one dollar and seventyfive cents ($1.75) for a single phase meter.
With respect to the second form of innefficiency, the utility company must initially absorb the higher equipment costs of the three phase meter and the transformer until the consumer has offset these fees as a function of time. A three phase, 200 amp meter costs approximately $150.00, while its single phase counterpart costs $30.00. In addition, power to a three phase installation requires a special voltage transformer costing $450.00. It is clear that both parties, the consumer and the utility company are engaged in a needless expenditure.
The expenditure that is wasted is further exacerbated by the fact that not only is the three phase meter initially five times more expensive than a single phase meter but it also requires periodic meter tests which are not required for a single phase meter. Meter tests are required on three phase meters within the first year of installation as well as on three phase meters that are over twelve years old.
Conventional wisdom with respect to replacing an unused three phase system with a one phase system includes the belief that a new tenant would be deterred from renting an establishment that does not have three phase capability. Thus, converting a three phase system to a one phase system is not viewed as desireable both by the utility company and by the property owner.
The following patents reflect the state of the art of which applicant is aware insofar as they appear relevant to the instant invention. These patents are included to fulfill the inventor's acknowledged duty to disclose relevant prior art and it is stipulated that these patents have limited relevance to the patentability of the instant invention.
______________________________________ 2,805,403 Road September 3, 1957 3,662,323 Stanback May 9, 1972 3,151,924 Sloop October 6, 1964 3,644,872 Russo, Jr. February 22, 1972 4,386,333 Dillan May 31, 1983 4,311,353 Adlerteg January 19, 1982 4,033,658 Asick July 5, 1977 ______________________________________
The patent to Road is informative since he chronicles the evolution of electrical power meters from 1946 and predicts the evolution of the meter to its present state. Thus, he notes that prior to 1956 a simple four terminal meter was prevalent, but that power demands initally led to five terminal meters which will have to be replaced by seven terminal meters to provide four wire service. It would appear that technology has come full circle since the Road patent since the instant invention is directed to a apparatus which converts a seven terminal, four wire service to a four terminal meter.
Sloop is of interest since his purpose is the inverse from that which is the object of the instant invention. Sloop teaches the use of an adapter by which a conventional light weight, single phase socket can be converted into a heavy duty meter socket so that heavy duty conductors can be used without damage thereto.
The remaining citations show the state of the art further.